Pregnant women and neonates metabolize drugs given during labor and delivery to both inactive and pharmacologically active metabolites. Whether this metabolism is altered by disease or immaturity has not been carefully studied. In fact, most studies have carefully eliminated high risk patients. The purpose of this study is to test the hypothesis that maternal and/or neonatal disease will affect the metabolism of pain relieving compounds given during labor. The two enzyme systems and representative drugs to be studied are: the cytochrome p 450 system (lidocaine) and the plasma cholinesterase system (nesacaine). These two drugs are to be studied because: 1) they are frequently used as necessary medications in high risk populations; 2) we have data as to the metabolism of these compounds in normal full term mothers and infants. Three groups of high risk patients and their infants are to be studied. These include: 1) diabetics; 2) normal patients with premature labor; and 3) those expected to deliver growth retarded infants. The study involves the gas chromatographic and mass spectrometric determination of drugs and metabolites in maternal plasma during labor, in cord blood, and in maternal and neonatal urine samples. The methodology and sample collection involved in this study design has previously been considered by the Human Investigation Committee and found to be without risk to either pregnant patients or neonates. The data provided by this study may allow for a more knowledgeable and perhaps more appropriate selection of drugs used in these high risk pregnancies.